The invention relates to a high-pressure gas discharge lamp comprising a translucent lamp vessel which is sealed in a vacuum-tight manner, which is filled with an ionizable gas and which has electrodes which project into the lamp vessel and are connected to current supply conductors extending through the wall of the lamp vessel to the exterior. Each electrode comprises a rod of mainly tungsten, which in the proximity of its tip projecting within the lamp vessel has a helical winding of wire of mainly tungsten, of which a first layer of turns is present around the rod and another layer of turns is arranged to surround the first layer. The first layer of turns locally having a turn of high pitch of at least the wire diameter of the first layer of turns plus the wire diameter of the other layer of turns, this winding being fixed on the rod and the wire of this winding having ends with end faces. Such a lamp is known from U.S. Pat. No. 3,170,081.
The purpose of the winding around the rod of an electrode is to obtain a satisfactory heat distribution over the electrode and to hold electron-emitting material.
It is mostly necessary to fix the winding on the rod, for example by deforming a turn in the hot state in order that it is clamped around the rod, or by welding the winding to the rod.
In the lamp according to the said U.S. Pat. No. 3,170,081, the first layer of turns is a body which is slipped with clearance around the rod and is fixed on it, while the other layer of turns is a separate body which is slipped around the first layer. In order to fix the second layer of turns, the first layer of turns has a projecting wire portion at its end remote from the tip of the rod of the electrode and the other layer of turns has at the corresponding end a wire portion which is bent towards the rod. This electrode construction renders the manufacture of the electrodes and hence of the lamp difficult.